Good TT for the price should not be as important as good TT for your needs.
I am picking up on "not exactly what we want" and "figure we can trade up in 3-5 years." The reason most often that people "trade up" is that what they bought turned out not to be what they really wanted. I see this too often in our local RV club, new RV every 2-3 years trying to find the one that works for they way they want to use it. There can be substantial losses trading in, though people sometimes do pretty well on private sales, especially if the RV is old enough to have depreciated to a "floor" price which is more like 10-15 years for TTs, 15-20 years for motorhomes.
I suggest looking for something used that is very similar to the new one you think you really wanted. That way you are more likely to be satisfied enough with your choice to keep it long term, because there isn't really much difference in utility of TTs made today vs 5 years ago or 10 years ago, from most of today's manufacturers. This is assuming that looking at a Gulfstream means that what you really want doesn't include any special or unusual types of TT construction.